1. Field of the Invention
The present invention relates to a supervisory camera system which is installed in various facilities, such as public facilities, stores and banking facilities, for the purpose of preventing crimes.
2. Description of the Related Art
A supervisory camera system is a system which monitors a supervisory area using a monitor camera. The system is generally installed in facilities of every kind which particularly require crime prevention, for example banks. Among conventional systems, there is a system in which an individual monitor camera is installed at every supervisory point. There is also another system in which a single monitor camera monitors a plurality of supervisory points in consideration of a reduction in system costs and limitation of the installation space.
In the latter system, a plurality of supervisory points previously set are monitored one by one in a prescribed order by a single monitor camera. Whenever a supervisory point is switched to another, a control function of the system is activated to change a posture of the monitor camera, a zooming extent, or the like.
However, in the conventional systems described above, there is a possibility that a person who attempts to commit a crime will learn the switching order of the supervisory points and the monitoring cycle if he or she observes the cyclic operation of the monitor camera for a while. Therefore, there is a fear of his or her conducting criminal activities during the intervals of supervision.
More specifically, in the conventional systems, the monitor camera operates in a regular manner and therefore future movements of the monitor camera can be easily predicted. Under such circumstances, there is a great need for a supervisory camera system which is very effective during preventing crimes.
In the Official Gazette of Japanese Patent Laid-Open Publication No. Hei 6-6644, a system related to household portable cameras is disclosed. In this conventional system, a portable video camera is mounted in a mechanism which holds the camera in such a manner that the camera is capable of rotating and going up and down. The constitution is such that the directions of image pickup and zooming extent of the camera can be easily adjusted by a remote control operation. Also in this system, a random number generator for generating random numbers every prescribed number of seconds is installed. Based on the random numbers generated, the directions of image pickup and zooming extent of the camera are automatically varied. However, the object of using these random numbers in this conventional system is to produce eye-catching video products. In this conventional system, images are picked up from random directions and changeovers of image pickup directions are performed at fixed intervals. Therefore, this conventional system is not suitable for supervisory purposes.